The reasons for the oil temperature of the transmission system of a hydraulic transmission bulldozer

The normal working oil temperature of the transmission system of a hydraulic transmission bulldozer is around 90℃. This temperature can be reflected by the oil temperature gauge on the instrument panel. If the pointer of the oil temperature gauge often points to the red zone, it indicates that the oil temperature of the bulldozer's transmission system is too high. High oil temperature can, at the very least, reduce work efficiency, and in severe cases, cause weak operation, posing a significant threat to machinery, especially to the sealing parts within the system, which cannot be ignored. This article briefly analyzes some of the main and common reasons for high oil temperature in transmission systems.

The main reasons for high oil temperature are, first, from the hydraulic system and, second, from the mechanical system. In summary, there are the following aspects:

(1) The performance of the hydraulic pump decreases. The hydraulic oil used in the variable speed and torque system is mainly provided by the variable speed pump. When the performance of the hydraulic pump declines, the oil supply to the system is insufficient, resulting in the hydraulic oil not being able to fully play its role as a medium. At the same time, it cannot fully lubricate the moving parts, increasing the friction between the moving parts and correspondingly raising the heat of the machinery. Moreover, the amount of hydraulic oil is less than the specified quantity. During the circulation, excessive heat cannot be removed in time, thus causing the oil temperature to be high.

(2) The variable speed control valve is faulty. The hydraulic system of a bulldozer is rather delicate, especially among various hydraulic control valves, and the variable speed valve is one of them. Poor cleanliness of the hydraulic oil or improper use and maintenance can cause the speed change valve to malfunction, resulting in insufficient oil supply to the torque converter. Especially for the 160-type bulldozer, the torque converter only has one hydraulic oil for the variable-speed torque system. A malfunction of the variable-speed valve will have a huge impact on the system. Generally speaking, the most direct and common fault is that the safety valve inside the variable speed valve gets stuck. The inlet and outlet pressures of the variable speed valve can be checked (the inlet pressure is the pressure of the variable speed safety valve, which is 2.5MPa; the outlet pressure is the pressure of the torque converter relief valve, which is between 0.5 and 0.9MPa). When the variable speed valve malfunctions, the main manifestation is low system pressure. The safety valve of the speed change valve should be removed and cleaned thoroughly to eliminate the fault.

(3) Insufficient oil in the system oil tank. The working environment of a bulldozer is generally harsh, with a steep slope and uneven terrain. Insufficient oil can cause the hydraulic pump to be sucked empty, failing to supply the normal oil supply to the hydraulic system. Therefore, it is very necessary to frequently check the oil level of the bulldozer. The bulldozer can be placed on a flat ground and the oil level on the dipstick should be checked. This oil level should reach the specified mark.

(4) The pipelines in the system are not unobstructed. The hydraulic oil in the system runs in the pipelines. The system pipelines are divided into two parts: before and after the pump. The fault phenomena of the two parts are not exactly the same. If the pipeline before the pump is not unobstructed, the system's oil suction volume will be insufficient, and it will often be accompanied by abnormal sounds, such as the friction sound of the hydraulic pump gears meshing and whistling. If the pipeline is not unobstructed at the rear part of the pump, it is usually caused by the filter element of the fine filter being clogged, which will prevent the hydraulic oil from smoothly reaching the hydraulic components such as the speed change valve and torque converter. Unobstructed pipelines also result in insufficient oil volume in the system, causing the oil temperature in the system to be too high. All kinds of filter elements in the system should be cleaned regularly, and some filter elements should be replaced at the prescribed time to reduce the occurrence of unobstructed system pipelines and avoid the resulting excessively high oil temperature. Atlas air compressor parts

(5) Abnormal oil return in the torque converter: The oil leaked from the torque converter is returned to the system oil tank through the coarse filter screen and the return oil pump. Once the oil return is abnormal, the amount of oil accumulated in the torque converter will exceed the specified quantity. The oil is stirred by the relevant components of the torque converter, generating a large amount of heat. At this time, due to the poor circulation of the hydraulic system, the heat carried away by the oil is relatively reduced. This causes the temperature of the torque converter to rise. If the return oil pump inside the torque converter is damaged or the filter screen before the pump is too dirty, it will cause abnormal oil return of the torque converter. The filter screen of the torque converter should be frequently inspected and cleaned, which is very helpful for ensuring the normal oil return of the torque converter.

Wechat Mini Program QR code